1. Field of the Invention
The invention pertains to a device for preventing the door leaves of a door system with at least one leaf used in an escape and rescue route from being swung unintentionally out of position.
2. Description of the Related Art
It is known that revolving doors, for example, have leaves which rotate around a central axis. The leaves extend between the central, pillar-like drive component and the boundary walls of the revolving door, which are designed in the form of segments of a cylinder. The leaves are supported on the central drive component in such a way that they can pivot, so that, after the revolving door has been stopped, a retaining force can be overcome and the leaves swung out of their normal, radially oriented operating position, in which they are perpendicular to the boundary walls as the revolving door revolves, into an open position, which allows free passage.
As a result, a rescue and escape route is opened, which makes it possible for people to pass through the revolving door without hindrance.
A design of this type also means that the revolving door can be stopped from revolving and the leaves opened in situations where this would be desirable, such as especially during the summer.
A comparable situation exists in the case of sliding door systems. A defined retaining force must again be overcome so that the sliding doors can be swung out of their normal position in which they are in a plane parallel to the stationary sidewalls into an open position which allows free passage in an emergency.
It is difficult to support doors of this type in such a way that they can be intentionally released and swung out of position because, first, the leaves of a revolving door must be held securely in their normal position, in which they can form an “X” in cross section, for example, when the door is revolving. Second, after the door has been stopped, it must be possible to swing the leaves aside by hand either when desired or after overcoming a predetermined retaining force and thus to move them into the position in which they allow free passage and thus create a rescue and escape route. Because the dimensions of such door systems and thus also of the leaves themselves are relatively large, the forces acting on the door during normal operation must also be taken into account.
As experience has shown, the retaining forces required for the leaves to withstand wind pressure are much higher than the forces which can be reasonably expected to be overcome when the leaves are to be opened in a panic situation. Because the positions of the door leaves are usually scanned for control purposes, situations in which the leaves have been unintentionally swung out of their normal positions can cause problems with the normal operation of the door and prevent the door from being moved at all. The door leaves must therefore always be held in their normal position in spite of the forces which may be acting on them, but it must also be possible to swing them out of the way in a panic situation.
For this purpose, a so-called “storm lock” is known from DE 40 36 881 C2, in which a stop device, which rotates around the central axis of the revolving door, can be brought into engagement with a partially elastic, pivotable retaining device to prevent the door leaves from swinging out of position until a force is exerted which is strong enough to swing at least part of the retaining device away from the stop device, thus making it possible for the door leaves to swing. The amount of this force, which acts on the retaining device, is predetermined by the stop device.
The retaining device has stop points, designed as cams. A roller, which is supported on a spring-loaded, four-bar linkage with adjustable elastic force, cooperates with the retaining device. The four-bar linkage can also be locked in position by means of an electromagnet.
The effort required to construct a device of this type is considerable; it is complicated to install; and it is difficult to adjust the elastic forces properly. In particular, however, because of the spring-loaded pretension of the four-bar linkage, the blocking action can be overridden by shock-like forces even when the electromagnets are active.
Latching devices for holding the leaves of revolving doors in position are also known. In this type of device, each leaf has its own drive, which pushes the leaf against a stop, which holds the leaf in place. The stop can be actuated by an electromagnetic retaining magnet; compare DE 44 42 191 A1.
This type of design is also very complicated to build and to install, because a drive, designed as a door closer, for example, must be provided for each door leaf, and each of these drives must develop enough torque to hold the door leaf in question against the controlled stop. To improve the retaining force, retaining magnets can also be provided.
In addition, the action of these types of door closers is dependent on the direction in which they operate, which means that an additional drive must be provided for each door leaf to return the leaf to its original position. This represents an additional complication in the construction of these types of revolving doors and also leads to additional expense.
A damping and retaining device with an electrical retaining magnet and an eddy-current brake, furthermore, is known from DE 90 00 881 U1. This device can be used in the drives of doors and gates.
Finally, latch catches which can be actuated by linear motors and which can serve to secure the leaves of a revolving door are also known. Compare EP 0 340 771.
As a result of their electromechanical complexity, however, it has been impossible to introduce these devices into widespread use.